jats:titleAbstract</jats:title>jats:pIn a ferromagnet/normal metal/ferromagnet spin-valve, spin dependent scattering causes a difference in resistance between antiparallel (AP) and parallel (P) magnetization states. The resistance difference, Δjats:italicR</jats:italic> = jats:italicR</jats:italic>(jats:italicA</jats:italic>jats:italicP</jats:italic>) − jats:italicR</jats:italic>(jats:italicP</jats:italic>) is positive due to increased scattering of majority and minority spin-electrons in the AP-state. If the normal metal is substituted for a superconductor, the superconducting spin-valve effect occurs: in the AP-state the net magnetic exchange field acting on the superconductor is lowered and the superconductivity is reinforced meaning jats:italicR</jats:italic>(jats:italicA</jats:italic>jats:italicP</jats:italic>) decreases. For current-perpendicular-to-plane spin-valves, existing experimental studies show that the normal state effect dominates (Δjats:italicR</jats:italic> > 0) over the superconducting spin valve effect (Δjats:italicR</jats:italic> < 0). Here however, we report a crossover from giant magnetoresistance (Δjats:italicR</jats:italic> > 0) to the superconducting spin-valve effect (Δjats:italicR</jats:italic> < 0) in current-perpendicular-to-plane ferromagnet/superconductor/ferromagnet spin-valves as the superconductor thickness decreases below a critical value.</jats:p>